Becky
Cann, Mark Stoneking, and Allan Wilson obtained mitochondrial
DNA from the placentas of women of various continental
origins. Comparative analysis of RFLP maps showed
that women ##1-8 (blue
dots) were all of African origin and formed a related
cluster that diverged from all other women (including others
of African origin). This finding was consistent with an African
origin of all modern humans, (the "Out
of Africa" hypothesis). The caclulated
divergence dtime of the most recent common ancestor
(the "Mitochondrial Eve") placed her far more
recently that previously supposed, only a few hundred
thousand years ago. [It should be emphasized that the
occurence of Eve is a consequence of population genetic
theory called coalesence, and does not mean that she
was the only woman alive at that time].